If you bought a computer a few years ago, it would invariably come with a free CD-Rom encyclopedia. At the time it seemed like a life-changer, but after an hour or two spent looking at ancient wildlife clips and a timeline about the Romans, the excitement wore off. Todayâ€™s internet equivalents are bigger, faster and more interactive, whether youâ€™re helping youngsters with their homework or cramming for the pub quiz.